Van-der-Waals (vdW) assembly enables the fabrication of novel Josephson junctions utilizing an atomically sharp interface between two exfoliated and relatively twisted Bi2Sr2CaCu2O8+x (Bi2212) flakes. In a range of twist angles around 45∘, the junction provides a regime where the interlayer two-Cooper pair tunneling dominates the current-phase relation. Here we propose to employ this novel junction to realize a capacitively shunted qubit that we call flowermon. The d-wave nature of the order parameter endows the flowermon with inherent protection against charge-noise-induced relaxation and quasiparticle-induced dissipation. This inherently protected qubit paves the way to a new class of high-coherence hybrid superconducting quantum devices based on unconventional superconductors.
@article{arxiv.2308.00839,
title = {Superconducting qubit based on twisted cuprate van der Waals heterostructures},
author = {Valentina Brosco and Giuseppe Serpico and Valerii Vinokur and Nicola Poccia and Uri Vool},
journal= {arXiv preprint arXiv:2308.00839},
year = {2023}
}